Previous research has suggested that negative emotions
like anxiety and anger can increase the risk for heart disease. But in the new study, depression -- and its physical symptoms -- was the emotional linchpin to early signs of heart disease.

"In other studies, anxiety, depression, anger and
hostility have all separately been linked to future risk of heart disease," said
lead researcher Jesse C. Stewart, a member of the psychology department at Indiana University-Purdue University Indianapolis. But the problem with those studies was that they didn't look at these negative emotions together. And since their symptoms can overlap, it has been hard to tell which emotion plays the most important role in heart disease, he said.

For the study, Stewart's team looked for emotional links to heart disease among 324 men and women with an average age of 60.6 years old. To determine early signs of heart disease, the scientists examined carotid artery
intima-media thickness, which is a measure of the inner layers of the arteries
and is related to early stage heart disease. Measurements were taken at the start of the study and again three years later.

"We found that mild to moderate depressive symptoms were associated with greater progression of subclinical atherosclerosis
[hardening of the arteries] -- greater increase of the artery wall," Stewart
said. "In contrast, anxiety symptoms, hostility and anger were not at all
related to a change in the blood vessel thickness."

What's more, analysis showed that only the physical symptoms of depression predicted the progression of atherosclerosis. And it appears that the symptoms of depression exist before the signs of atherosclerosis, Stewart said.

The findings are published in the February issue of the Archives of General Psychiatry.

Stewart isn't sure why depression has this effect. "Depression has been associated with some physiological changes, including in the immune system. These physiological changes probably explain this association," he said.

The study also found that the 5 percent of study participants taking antidepressants fared better than those with depression who weren't taking the drugs. "They had significantly reduced progression of atherosclerosis," Stewart said.

But, because the sample was so small, it isn't possible to make a definitive statement about the value of selective serotoninreuptake inhibitors (SSRIs) in reducing atherosclerosis, Stewart said. "There is intriguing evidence that SSRIs may be associated with reduced progression of atherosclerosis," he said.

Stewart thinks the study findings may help in treating and preventing heart disease.

"Identifying the harmful aspects of emotion could lead
to the identification of people who are at risk for heart disease due to their
tendency to experience negative emotions and who may benefit from psychological
and pharmacological intervention," he said. "Identifying these harmful aspects could also lead to the development of more focused and potent interventions."

Dr. Nieca Goldberg, chief of women's cardiac care at
Lenox Hill Hospital in New York City, noted that depressed people are less likely to take care of themselves and have more risk factors for heart disease.

"People who are depressed don't adopt a healthy lifestyle," said Goldberg, a spokeswoman for the American Heart Association and author of The Women's Healthy Heart Program. "They overeat, smoke more, may drink more. In addition, people who have depression have platelets that are more likely to clot."

Goldberg thinks doctors should pay closer attention to
depression and other psychological factors that can affect patient health.

"For too long, the medical system has amputated the head
from the rest of the body," she said. "It is important for us to consider the psychological aspects of our patients' lives, because that is an important factor in our care of a patient."